Field of the Disclosure
The present disclosure, for example, relates to wireless communication systems, and more particularly to synchronizing and desynchronizing contention for access to a plurality of channels of an unlicensed radio frequency spectrum band.
Description of Related Art
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).
In some wireless communication systems, base stations and UEs may communicate on an enhanced component carrier (eCC) in an unlicensed radio frequency spectrum band. Prior to gaining access to and communicating over an eCC, the base station or UE may contend for access to a plurality of channels of an unlicensed radio frequency spectrum band. Contending for access to each channel of the unlicensed radio frequency spectrum band may include performing a listen before talk (LBT) procedure for each channel. An LBT procedure may include performing a clear channel assessment (CCA) procedure or an extended CCA (eCCA) procedure, to determine whether a channel of the unlicensed radio frequency spectrum band is available. When it is determined that the channel of the unlicensed radio frequency spectrum band is available, a channel reservation signal (e.g., a channel usage beacon signal (CUBS)) may be transmitted to reserve the channel. A device that receives the channel reservation signal may defer accessing the channel.